Vacuum-based strategy for production of super-hydrophilic nanostructured SiOx coatings on conventional polymers was developed. This method is based on pre-seeding of polymers with Ag nanoparticles fabricated by means of gas aggregation source of nanoparticles prior to the SiOx deposition. It is shown that at a sufficiently large amount of Ag nanoparticles the produced coatings exhibited nanotexture that possessed temporally stable super-hydrophilic character with water contact angles lower than 10 degrees for a period of 2 years. (C) 2018 Elsevier B.V. All rights reserved.

Recent works have shown the potential applicability of gas aggregation cluster sources (GAS) for the synthesis of plasma polymer nanoparticles (NPs). However, deep understanding of the fundamentals of the NP formation is still lacking because the research has been focused mainly on ex-situ analysis of the NPs rather than on the processes taking place inside the cluster source. In this work, we simultaneously employed optical emission spectroscopy, mass spectrometry and digital camera to monitor in situ the phenomena occurring during the synthesis of hydrocarbon NPs by plasma polymerization of n-hexane. The voltage on the electrode and the deposition rate of the NPs were also real-time tracked. A 3-inch RF electrode was operated at a constant power of 50 W in a 4.6 % mixture of n-hexane with argon. Cycling instabilities in the deposition process were detected. The temporal measurement of both the voltage and the deposition rate revealed the period of oscillations to be about 80 s. These oscillations correlated with the instabilities observed in the mass spectra where analogous oscillations of the n-hexane molecular peak were detected. The temporal instabilities were further proved by optical emission spectra in which the intensity of the Ar spectral line was seen to oscillate with the same period. A phenomenological description was suggested to describe the cycling growth of the NPs and their ejection from the discharge zone. Acknowledgments: The authors would like to acknowledge the contribution of the COST Action CA15107 (MultiComp) and support by the grant LTC17062 from the Ministry of Education, Youth and Sports of the Czech Republic.

In this work, we applied a method of light scattering for in situ detection of organosilicon nanoparticles (NPs). Plasma polymerization of hexamethyldisiloxane (HMDSO) in its 10 % mixture with Ar was used to synthesize the NPs by means of a gas aggregation cluster source (GAS). The total pressure of 45 Pa and the RF discharge power in a range of 20 - 80 W were used. The GAS was constructed to allow passing of a laser beam (446 nm) across the beam of the NPs at the distance of 2 cm behind the exit orifice and acquiring the scattered light either by an optical emission spectrometer or by a CCD camera. Although for 20 W power constant intensity of the scattered light was obtained, cycling instabilities were detected for higher power. Both amplitude and period of such fluctuations increased with the discharge power increasing from 40 to 80 W. Cycling repelling of NPs and formation of plasma voids are suggested as possible mechanisms for the observed phenomena.

Core@shell Cu/hydrocarbon plasma polymer nanoparticles (NPs) have been prepared using a gas aggregation cluster source followed by in-flight plasma polymer coating of produced Cu NPs. Conventional plasma polymerization of vapors of n-Hexane or acetone has been applied. It is shown that this strategy for core@shell NPs production enables to achieve homogeneous shells with thickness in nanometer scale without impact on the properties of metallic cores (crystallinity, optical properties). In addition, it has been proved that the chemical properties of shells may be controlled by use of different organic precursors that enables production of NPs with different wettabilities.

This work investigates plasma instabilities occurring in a Gas Aggregation Cluster Source (GAS) and correlates them with the formation and growth of hydrocarbon nanoparticles (NPs). For this aim, special configuration of the GAS was employed, which allows for simultaneous measurements of the discharge voltage, the optical emission (OES) and the mass spectra (MS). Cycling instabilities with a period of 80 s were detected in the deposition rate which correlated with the changes in the discharge voltage, the intensity of the plasma emission and the concentration of hydrocarbon species.

This contribution reviews plasma polymer nanoparticles produced by gas aggregation cluster sources either via plasma polymerization of volatile monomers or via radio frequency (RF) magnetron sputtering of conventional polymers. The formation of hydrocarbon, fluorocarbon, silicon- and nitrogen-containing plasma polymer nanoparticles as well as core@shell nanoparticles based on plasma polymers is discussed with a focus on the development of novel nanostructured surfaces.

Bio-decontamination of surfaces by means of atmospheric pressure plasma is nowadays extensively studied as it represents promising alternative to commonly used sterilization/decontamination techniques. The non-equilibrium atmospheric pressure plasmas were already reported to be highly effective in removal of a wide range of biological residual from surfaces. Nevertheless the kinetics of removal of biological contamination from surfaces is still not well understood as the majority of performed studies were based on ex-situ evaluation of etching rates, which did not allow investigating details of plasma action on biomolecules. This study therefore presents a real-time, in-situ ellipsometric characterization of removal of bovine serum albumin (BSA) from surfaces by low-temperature atmospheric plasma jet operated in argon. Non-linear and at shorter distances between treated samples and nozzle of the plasma jet also non-monotonic dependence of the removal rate on the treatment duration was observed. According to additional measurements focused on the determination of chemical changes of treated BSA as well as temperature measurements, the observed behavior is most likely connected with two opposing effects: the formation of a thin layer on the top of BSA deposit enriched in inorganic compounds, whose presence causes a gradual decrease of removal efficiency, and slight heating of BSA that facilitates its degradation and volatilization induced by chemically active radicals produced by the plasma. (C) 2016 Elsevier B.V. All rights reserved.

A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and maintaining the multivalued character of the surface roughness. The growth (β) and the dynamic (1/z) exponents are close to zero and the interface bears the features of self-affinity. The presence of inter-particle voids leads to heterogeneous wetting with an apparent water contact angle θa = 135°. The multivalued nanotopography results in two possible positions for the water droplet meniscus, yet strong water adhesion indicates that the meniscus is located at the lower part of the spherical nanofeatures. In the late regime, the inter-particle voids become filled and the interface acquires a single valued character. The plasma polymer proceeds to grow on the thus-roughened surface whereas the nanoparticles keep emerging away from the substrate. The RMS roughness remains invariable and lateral correlations propagate with 1/z = 0.27. The surface features multiaffinity which is given by different evolution of length scales associated with the nanoparticles and with the plasma polymer. The wettability turns to the homogeneous wetting state.

Silver-based nanomaterials that exhibit antibacterial character are intensively studied as they represent promising weapon against multi-drug resistant bacteria. Equally important class of materials represent coatings that have highly water repellent nature. Such materials may be used for fabrication of anti-fogging or self-cleaning surfaces. The aim of this study is to combine both of these valuable material characteristics. Antibacterial and highly hydrophobic Ag/C:F nanocomposite films were fabricated by means of gas aggregation source of Ag nanoparticles and sputter deposition of C:F matrix. The nanocomposite coatings had three-layer structure C:F base layer/Ag nanoparticles/C:F top layer. It is shown that the increasing number of Ag nanoparticles in produced coatings leads not only in enhancement of their antibacterial activity, but also causes substantial increase of their hydrophobicity. Under optimized conditions, the coatings are super-hydrophobic with water contact angle equal to 165[Formula: see text] and are capable to induce 6-log reduction of bacteria presented in solution within 4[Formula: see text]h.

Immiscible polymer blends tend to undergo phase separation with the formation of nanoscale architecture which can be used in a variety of applications. Different wet-chemistry techniques already exist to fix the resultant polymeric structure in predictable manner. In this work, an all-dry and plasma-based strategy is proposed to fabricate thin films of microphase-separated polyolefin/polyether blends. This is achieved by directing (-CH2-)100 and (-CH2-CH2-O-)25 oligomer fluxes produced by vacuum thermal decomposition of poly(ethylene) and poly(ethylene oxide) onto silicon substrates through the zone of the glow discharge. The strategy enables mixing of thermodynamically incompatible macromolecules at the molecular level, whereas electron-impact-initiated radicals serve as cross-linkers to arrest the subsequent phase separation at the nanoscale. The mechanism of the phase separation as well as the morphology of the films is found to depend on the ratio between the oligomeric fluxes. For polyolefin-rich mixtures, polyether molecules self-organize by nucleation and growth into spherical domains with average height of 22 nm and average diameter of 170 nm. For equinumerous fluxes and for mixtures with the prevalence of polyethers, spinodal decomposition is detected that results in the formation of bicontinuous structures with the characteristic domain size and spacing ranging between 5 × 10(1) -7 × 10(1) nm and 3 × 10(2)-4 × 10(2) nm, respectively. The method is shown to produce films with tunable wettability and biologically nonfouling properties.

Surfaces whose properties change gradually along the sample length, so‐called gradient surfaces, are highly interesting for fundamental studies focused on the interaction between biomolecules or cells and surfaces. In this study, we investigate simple, vacuum‐based strategy for fabrication of surfaces with gradient nanoroughness and wettability. This approach is based on the application of gas aggregation source of nanoparticles combined with the magnetron sputtering of poly(tetrafluoroethylene). It is shown that this technique makes it possible to produce coatings with invariant surface chemistry, but with gradient roughness in the range 0.5–20 nm and wettability gradient that ranges from 100° up to 150°, i.e., coatings with hydrophobic to superhydrophobic character.

Silver nanoparticle-based antibacterial nanocomposite coatings were fabricated by means of gas aggregation source of Ag nanoparticles and plasma-enhanced chemical vapour deposition of matrix material. Combination of these techniques makes it possible to independently control the amount of Ag nanoparticles in the nanocomposites, as well as properties of matrix material, such as its chemical composition or wettability. This subsequently enables to tune kinetics of silver ion release and hence the antibacterial performance of produced nanocomposites. Based on detail measurements of silver ion release from Ag/plasma polymerized hexamethyldisiloxane and Ag/SiOx nanocomposites, it may be concluded that the release rate is strongly dependent both on matrix material and amount of Ag nanoparticles present in the nanocomposite. These measurements are furthermore accompanied with tests focused on the evaluation of antibacterial potency of produced nanocomposites.

Biomimetic nano-structured films are valuable materials in various applications. In this study we introduce a fully vacuum-based approach for fabrication of such films. The method combines deposition of nanoparticles (NPs) by gas aggregation source and deposition of overcoat thin film that fixes the nanoparticles on a surface. This leads to the formation of nanorough surfaces which, depending on the chemical nature of the overcoat, may range from superhydrophilic to superhydrophobic. In addition, it is shown that by proper adjustment of the amount of NPs it is possible to tailor adhesive force on superhydrophobic surfaces. Finally, the possibility to produce NPs in a wide range of their size (45-240 nm in this study) makes it possible to produce surfaces not only with single scale roughness, but also with bi-modal or even multi-modal character. Such surfaces were found to be superhydrophobic with negligible water contact angle hysteresis and hence truly slippery.

Atmospheric air plasma treatment of chitosan solutions leads to degradation of chitosan molecules by OH radicals and is accompanied by a predominant cleavage of glycosidic linkages and by a decrease of the molecular weight. The degradation proceeds via first order kinetics with the rate constant of (5.73±0.22)×10(-6)s(-1) and the energetic yield of chitosan bond scission of (2.4±0.2)×10(-8)mol/J. Products of degradation together with intact chitosan molecules adsorb and form coatings on polypropylene foils immersed into the solution that is being plasma treated. The plasma treatment results in strong binding of chitosan to polypropylene due to the formation of covalent bonds between the activated polymer surface and chitosan molecules. Plasma-driven crosslinking is responsible for the accumulation of compressive stress which leads to the development of buckling instabilities in the chitosan coatings.

Hydrocarbon polymer films (ppCH) enriched with various concentrations of titanium were deposited on microscopic glass slides by magnetron sputtering from a Ti target. The maximum concentration of Ti (about 20 at.%) was achieved in a pure argon atmosphere. The concentration of Ti decreased rapidly after n-hexane vapors were introduced into the plasma discharge, and reached zero values at n-hexane flow of 0.66 sccm. The decrease in Ti concentration was associated with decreasing oxygen and titanium carbide concentration in the films, decreasing wettability (the water drop contact angle increased from 20 to 91) and decreasing root-mean-square roughness (from 3.3 nm to 1.0 nm). The human osteoblast-like MG-63 cells cultured on pure ppCH films and on films with 20 at.% of Ti showed relatively high concentrations of ICAM-1, a marker of cell immune activation. Lower concentrations of Ti (mainly 5 at.%) improved cell adhesion and osteogenic differentiation, as revealed by higher concentrations of talin, vinculin and osteocalcin. Higher Ti concentrations (15 at.%) supported cell growth, as indicated by the highest final cell population densities on day 7 after seeding. Thus, enrichment of ppCH films with appropriate concentrations of Ti makes these films more suitable for potential coatings of bone implants. (C) 2015 Elsevier B.V. All rights reserved.

Flat and nanostructured thin films were fabricated by deposition of ultra-thin (<2 nm) layer of hydrocarbon plasma polymer over polished silicon and over a pattern of 8 nm-thick poly( ethylene) islands on silicon. Linker-free radical-based covalent binding of bovine serum albumin and tropoelastin was confirmed for both types of films. The binding capability of albumin was found to be stable over many days of ambient air storage time. Tropoelastin-mediated flat plasma polymers favored adhesion and proliferation of osteoblast-like MG-63 cells. Nanostructured plasma polymers were multi-affine and their hierarchical surface represented an additional barrier for cell attachment. (C) 2015 Elsevier B.V. All rights reserved.

In this contribution an effect of dielectric barrier discharge (DBD) sustained in air at atmospheric pressure on surface properties of poly(ethylene terephthalate) (PET) foils is studied. It is found that exposure of PET to DBD plasma leads to rapid changes of surface chemical composition, wettability, surface morphology as well as mechanical properties of PET surface. In addition, based on biological tests that were performed using two cell types (Saos-2 human osteoblast-like cells and HUVEC human umbilical vein endothelial cells), it may be concluded that DBD plasma treatment positively influences cell growth on PET. This effect was found to be connected predominantly with increased surface energy and oxygen content of the surface of treated PET foils. (C) 2015 Elsevier B.V. All rights reserved.